1. Field of the Invention
The present invention relates generally to reference sources and target designator systems, and more particularly, to integrated reference source and target designator systems for high-precision guidance of guided munitions.
2. Prior Art
In general, a human or machine (such as an “Unmanned Aerial Vehicle” (UAV), or an “Unmanned Ground Vehicle” (UGV) or a manned aerial or ground vehicle, or the like) is used to identify a target. Some means (e.g., one or more of the systems and devices such as “Global Positioning System” GPS, range finders, inertial devices, etc.) are then used to determine the position of the target and other relevant target indication information. Hereinafter, the above human or machine that is used to determine the position of the target is referred to generally as the “forward observer”.
In general, the position of the target is determined by the “forward observer” and is indicated relative to the earth. The “forward observer” must also determine its own position relative to the earth. The weapon platform that is to engage the target must also know its own position relative to the earth. The target position and other information that is acquired by the “forward observer” is then passed to the engaging weapon platform fire controller (usually a computer), which would then perform proper computations and pass target position and other guidance and control information to the guided munitions that is to be launched against the designated target. Once launched, the guided munitions will use the target position information (and sometimes target position updates when it is available) to guide itself to the designated target position. Near the target, guided munitions may, when equipped with some type of homing sensors, also use the latter sensors to guide them to the target.
As indicated above, in most current munitions guidance and control systems, the position of the target is determined by the forward observer relative to the earth, i.e., the earth is considered to be the reference system in which the position of the target, the weapon platform, and the forward observer is defined. In addition, the guided munitions, such as a projectile fired from a gun or a mortar shell, monitors its position relative to the same earth based (fixed) position reference system. There is, however, a positioning error relative to each one of the above four position measurements relative to the earth fixed position reference system. As a result, the four position error measurements add up to make up the amount of positioning error that the guided munitions will have relative to the target that it is desired to intercept, leading to a significant degradation of the precision with which a target could be intercepted.
In general, the only method available for increasing the precision with which guided munitions can be guided to intercept the target is by providing some type of homing device. Such homing systems may, for example, include target seekers such as heat seeking sensors or various guidance systems utilizing laser designators, etc. Such homing systems usually require sophisticated sensory devices that occupy relatively large spaces onboard and require relatively high onboard power to operate, which make them unsuitable for many munitions applications, particularly gun-fired munitions (particularly small and medium caliber munitions) and mortars. In addition, homing systems using various target designators such as laser target designator generally requires a forward target observer, usually a human, to designate the target, which is also not a desirable solution.
A need therefore exists for a method and apparatus that can be used to significantly increase the precision with which a target position can be provided to guide guided munitions without requiring aforementioned homing systems or the like seekers.
An object of the present invention is to provide such a method and apparatus that can be used in munitions, particularly in gun-fired munitions and mortars, to provide significantly higher precision with which the position of the target is provided to munitions for guidance to intercept a designated target.
Another object of the present invention is to provide a method and apparatus that provides higher target position precision to guided munitions without requiring onboard seekers.
Another object of the present invention is to provide a method and apparatus that provides higher target position precision to guided munitions using the aforementioned polarized RF position and orientation sensors and polarized RF sources such that not only the position of the target becomes known to guided munitions during their flights but information is also provided to the guided munitions as to their orientation relative to the target. The latter orientation information is essential for munitions guidance and control, since by knowing its orientation relative to the target at all times, the guided munitions can perform its guidance maneuvers with minimal control actuation efforts, thereby requiring smaller actuation devices and less power for guidance and control. As a result, less volume will need to be occupied by the latter components, thereby making it possible to provide guidance and control components to munitions without degrading their effectiveness, particularly for smaller caliber munitions.